PowerBook 3400c Capacitor Replacement Guide
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Capacitor values for the PowerBook 3400c. The machine has few electrolytics: one on the logic board, two on the DC power board, two on the Sharp display and two on the inverter board, which also drives the subwoofer. Apple's Service Source works at module level and gives no component values, so the list comes from MacDat's capacitor reference.[1][2]
When to recap
[edit | edit source]MacDat found in 2024 that the 3400c rarely needed a recap, but had heard of failing capacitors on the DC power board stopping machines from booting.[1] A 3400 that chimed and then made siren noises with a dark screen turned out to have a stuck hard disk; recapping its DC board and logic board, three capacitors in all, made no difference, so rule out the drive first.[3] See Capacitor Failure Symptoms.
Capacitor list
[edit | edit source]| Board | Value | Voltage | Count | Type | Diameter |
|---|---|---|---|---|---|
| Logic board | 33 µF | 25 V | 1 | Surface-mount electrolytic | |
| DC power board | 100 µF | 35 V | 1 | Surface-mount electrolytic | |
| 33 µF | 25 V | 1 | Surface-mount electrolytic | ||
| Display (Sharp LQ12S11) | 220 µF | 4 V | 1 | Surface-mount electrolytic | 6 mm |
| 22 µF | 16 V | 1 | Surface-mount electrolytic | 5 mm | |
| Inverter and subwoofer board | 10 µF | 50 V | 1 | Surface-mount electrolytic | 6 mm |
| 2.2 µF | 50 V | 1 | Surface-mount electrolytic | 3 mm |
MacDat notes a Samsung display fitted to some 3400c machines that uses only solid-state capacitors; check which panel you have.[1]
-
Logic board: 33 µF 25 V (MacDat) -
Sharp LQ12S11 display: 220 µF 4 V and 22 µF 16 V (MacDat) -
Inverter board: 10 µF 50 V and 2.2 µF 50 V (MacDat)
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Replacement procedure
[edit | edit source]Unplug the adapter and remove the battery first.[2]
DC power board
[edit | edit source]- Remove the floppy or CD-ROM drive and the keyboard, then the brightness and speaker grill (with the backup battery stuck under it), the clutch covers, the palm rest and the hard drive.[2]
- The power supply board's connector is on its top right side. Grasp the top edges of the board and lift it straight up and off, so the connector is not damaged.[2]
- Replace the two capacitors and refit the board straight down onto its connector.
Logic board
[edit | edit source]After the power supply board, remove the heatsink and the Ethernet or Ethernet and modem card. Unplug the display cable; lift the PCMCIA switch board straight up so its pins do not bend; unplug the LED connector and free its cable from the five tabs on the CPU stiffener; lift off the airflow deflector and unplug the fan. Ease the left side of the bottom case outwards and lift the board out by its right corner. Refit the PCMCIA switch board carefully, because its pins bend easily.[2]
Display and inverter
[edit | edit source]With the display assembly off, remove the two name plates with a plastic swizzle stick, then the two bumpers and four screws from the bezel, and prise the housing off at its eight inner latches starting at the clutch end. Remove the six display frame screws. Raise the inverter frame slightly so it does not touch the display, unplug the backlight and display connectors, release the inverter board's tab and lift it off. Apple warns against pressing on the display, which can crack. On reassembly, line the inverter frame up with the M-shaped guide line on the display shield, lay the backlight cable flat in its guide, and fit new kapton tape.[2]
Tools and parts
[edit | edit source]- T-8 and T-6 Torx drivers, a small flat-blade screwdriver, a dental pick for flex connectors and a plastic swizzle stick, as Apple lists.[2]
- A fine-tipped iron or hot air, flux, and isopropyl alcohol.
- Replacement parts no larger than the originals, particularly the 3 mm 2.2 µF part on the inverter board; see Recommended Tools.
After the recap
[edit | edit source]- Check that the machine boots on the adapter and on battery, and that the backlight lights and dims.
- Listen for crackling from the speakers as the machine warms up; MacDat's author heard it now and then after recapping, though it always cleared once the machine had booted.[1]
Related pages
[edit | edit source]- PowerBook 3400c
- PowerBook 3400c General Maintenance
- PowerBook 3400c Troubleshooting
- Battery Explosion, Capacitor or Corrosion Damage
References
[edit | edit source]- ↑ 1.0 1.1 1.2 1.3 1.4 MacDat Capacitor Reference Library, "PowerBook 3400c Capacitor Reference" (retrieved 2026-10-02). Logic board one 33 µF 25 V; DC/DC power board one 100 µF 35 V and one 33 µF 25 V; Sharp LQ12S11 display one 220 µF 4 V (6 mm) and one 22 µF 16 V (5 mm), with a Samsung display that uses only solid-state capacitors; inverter/subwoofer board one 10 µF 50 V (6 mm) and one 2.2 µF 50 V (3 mm). Notes that in 2024 the 3400c rarely needed a recap, that failing DC power board capacitors have been reported to stop units booting, and that the author's machine sometimes crackled from the speakers while warming up after the recap. Secondary source.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Apple Computer, PowerBook 3400c/PowerBook G3 Service Source (210 pp., this copy last modified August 1999), hosted here as File:PowerBook 3400c and PowerBook G3 Service Source.pdf (see PowerBook 3400c and PowerBook G3 Service Source). Module-level only. PDF page numbers: tools p. 80; Battery pp. 83-84; Keyboard pp. 91-95; Brightness & Speaker Grill pp. 98-100; Clutch Covers pp. 101-103; Palm Rest pp. 104-106; Hard Drive pp. 114-117; Power Supply Board pp. 118-119; Logic Board pp. 124-128; Display Assembly pp. 160-163; Display Housing pp. 164-168; Display Frame pp. 171-176; Inverter Board pp. 177-181.
- ↑ TinkerDifferent forum thread "PowerBook 3400 siren song", Elemenoh, starlite and others, May-June 2024. A stuck IBM Travelstar disk caused siren noises and a dark screen; a recap of the DC board and logic board did not help. Community experience.